AmpFℓSTR® Profiler Plus™ Short Tandem Repeat DNA Analysis of Casework Samples, Mixture Samples, and Nonhuman DNA Samples Amplified under Reduced PCR Volume Conditions (25 µL)

Abstract As part of the validation of the AmpFℓSTR® Profiler Plus™ short tandem repeat (STR) system, under reduced polymerase chain reaction (PCR) volume conditions (i.e., 25 µL), a total of 275 casework samples were processed. Examples of profiles are presented along with amplification conditions to improve the odds of obtaining balanced and complete profiles for samples showing partial results or profiles with a descending slope. Data collected and used to develop our interpretation guidelines are included. From the mixture studies, full profiles were obtained for minor contributors, using 2 ng of DNA, with ratios of 10:1 or 1:20 and using 1 ng of DNA, with ratios of 10:1 and 1:8. The specificity of the Profiler Plus™ amplification reaction performed in 25 µL was examined and confirmed using a large spectrum of nonhuman DNAs. This report supports the use of the AmpF€STR® Profiler Plus™ STR system for casework DNA typing under reduced PCR volume conditions.